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Table 2

Summary of PIAAN tolerances.

Parameters Tolerance MCMC value Comment
Wavefront errors

Tip-tilt ±0.18 λ/D Jitter, ADC residual
Coma λ/200 RMS
XAO residual λ/75 RMS in 3 cycles

PIAA optics

L1-L2 distance ±0.30% Can be measured before diamond turning
L1-L2 misalignment ±0.010 Dpupil ±0.01 Dpupil PTP Limited by chromatism in rod design
Pupil misalignment ±0.025 Dpupil ±0.005 Dpupil PTP Easy to align from PIAA pupil image
Pupil magnification ±0.020 Dpupil Pupil can be redefined at PIAA level
Pupil mask to PIAA distance ±3 cm ±1 cm PTP

IFU

fL3 and MLA size ±5% 1% RMS As measured
L3 defocus ±λ/20 RMS λ/20 RMS
Alignment to PIAA axis ±0.3 λ/D
fMLA and SMF MFD ±10% 3% RMS As measured in Sect. 4.1.1
Near-field alignment ±0.1 MFD 0.03 MFD RMS
Far-field alignment ±1° 0.06° RMS As measured in Sect. 4.1.2

Notes. Tolerance value is given as the limit ensuring ⟨ρ⟩ ≤ 7 · 10−5 for a single defect. We also give parameters of MCMC analysis with PTP value for a uniform distribution, and RMS for a Gaussian one. Those set to 0 are believed to be under control.

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